tagg2/src/createPool.js

full name is threads_a_gogo2,it is a cross platform support, Simple and fast JavaScript threads for Node.js

(function createPool (n) {
  'use strict';
  
  //2011-11 Proyectos Equis Ka, s.l., jorge@jorgechamorro.com
  //threads_a_gogo_createPool.js
  
  var T= this;
  
  n= Math.floor(n);
  if (!(n > 0)) {
    throw '.createPool( numOfThreads ): numOfThreads must be a Number > 0';
  }
  
  var kTypeRun= 1;
  var kTypeEmit= 2;
  var pool= [];
  var idleThreads= [];
  var q= { first:null, last:null, length:0 };
  var poolObject= {
    any: { eval:evalAny, emit:emitAny },
    all: { eval:evalAll, emit:emitAll },
    on: on,
    totalThreads: function getNumThreads () { return pool.length },
    idleThreads: function getIdleThreads () { return idleThreads.length },
    pendingJobs: function getPendingJobs () { return q.length },
    destroy:destroy,
    load:poolLoad
  };
  
  try {
    while (n--) {
      pool[n]= idleThreads[n]= T.create();
    }
  }
  catch (e) {
    destroy(1);
    throw e;
  }



  function poolLoad (path, cb) {
    var i= pool.length;
    while (i--) {
      pool[i].load(path, cb);
    }
  }


  function nextJob (t) {
    var job= qPull();
    if (job) {
      if (job.type === kTypeRun) {
        t.eval(job.srcTextOrEventType, job.buf, function idleCB (e, d) {
          nextJob(t);
          var f= job.cbOrData;
          if (f) {
            job.cbOrData.call(t, e, d);
          }
        },job.dirname);
      }
      else if (job.type === kTypeEmit) {
        t.emit(job.srcTextOrEventType, job.cbOrData);
        nextJob(t);
      }
    }
    else {
      idleThreads.push(t);
    }
  }



  function qPush (srcTextOrEventType, cbOrData, type,  buf, dirname) {
    var job= { next:null, srcTextOrEventType:srcTextOrEventType, cbOrData:cbOrData, type:type };
	if(buf) job.buf = buf;
	if(dirname) job.dirname = dirname;

    if (q.last) {
      q.last.next= job;
      q.last= job;
    }
    else {
      q.first= q.last= job;
    }
    q.length++;
  }



  function qPull () {
    var job= q.first;
    if (job) {
      if (q.last === job) {
        q.first= q.last= null;
      }
      else {
        q.first= job.next;
      }
      //job.next= null;
      q.length--;
    }
    return job;
  }



  function evalAny (src, buf, cb, dirname) {
    qPush(src, cb, kTypeRun, buf, dirname);
    if (idleThreads.length) {
      nextJob(idleThreads.pop());
    }
    
    return poolObject;
  }



  function evalAll (src, cb) {
    pool.forEach(function (v,i,o) {
      v.eval(src, cb);
    });
    
    return poolObject;
  }



  function emitAny (event, data) {
    qPush(event, data, kTypeEmit);
    if (idleThreads.length) {
      nextJob(idleThreads.pop());
    }
    
    return poolObject;
  }



  function emitAll (event, data) {
    pool.forEach(function (v,i,o) {
      v.emit(event, data);
    });
    
    return poolObject;
  }



  function on (event, cb) {
    pool.forEach(function (v,i,o) {
      v.on(event, cb);
    });
    
    return this;
  }


  function destroy (rudely) {
    function err () {
      throw 'This thread pool has been destroyed';
    }
    
    function beNice () {
      if (q.length) {
        setTimeout(beNice, 666);
      }
      else {
        beRude();
      }
    }
    
    function beRude () {
      q.length= 0;
      q.first= null;
      pool.forEach(function (v,i,o) {
        v.destroy();
      });
      poolObject.eval= poolObject.totalThreads= poolObject.idleThreads= poolObject.pendingJobs= poolObject.destroy= err;
    }
    
    rudely ? beRude() : beNice();
  }



  return poolObject;
})